Cardiac symptoms may be first sign of FA in children: Study

Genetic testing recommended to confirm FA diagnosis in children

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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Thickening of the heart muscle, although rare, may be the first manifestation of Friedreich’s ataxia (FA) in children, according to a new study.

These findings suggest genetic testing to confirm the FA diagnosis should be considered in children with unexplained hypertrophic cardiomyopathy, when the walls of the left ventricle become thick and stiff, researchers suggest.

Their study, “Characterization of Cardiac-Onset Initial Presentation in Friedreich Ataxia,” was published in the journal Pediatric Cardiology.

FA is caused by mutations in the FXN gene, which lead to deficiency of frataxin, an essential protein for the normal functioning of mitochondria. Dysfunctional mitochondria fail to meet the energy requirements of high-demanding cells, particularly those in muscles, leading to muscle weakness that significantly affects walking, upper limb movements, speech, and swallowing.

Besides the hallmark symptom of ataxia, characterized by lack of coordination and balance, FA patients may also experience cardiomyopathy and other heart problems.

In the study, a team of researchers from various institutions reviewed the clinical features of FA patients enrolled in the Friedreich’s Ataxia Clinical Outcome Measures Study — a natural history study of FA bringing together an international network of clinical research centers. A natural history study assesses how a disease progresses in the absence of treatment.

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3.1% of patients had cardiac symptoms as dominant disease symptom

Among a total of 1,420 patients, 44 (3.1%) had cardiac symptoms as the dominant disease manifestation. The most common symptoms were ataxia (83.2%), followed by scoliosis (5.7%), a sideways curvature of the spine. Across all groups, there was a delay between first symptoms and FA diagnosis.

Patients with cardiac abnormalities initially were significantly younger and had earlier disease onset — at a mean of 7.7 years — compared to patients with ataxia symptoms (13.6 years), scoliosis (11.6 years), and other symptoms.

Cardiac issues were found in 6.3% of children who were younger than 8 when their symptoms showed up, a higher percentage than in the overall study population. Still, neurological issues were the most frequent presentations of FA also in this young group (83.1%). Diabetes and other presentations were similar to the overall group, but scoliosis was less common (2.8%).

The researchers then analyzed further the 44 patients with cardiomyopathy as a first disease manifestation, including an additional six participants with earlier cardiac symptom onset. Ten patients showed no symptoms, and 11 had modest symptoms, including syncope (fainting), exercise intolerance, or chest pain.

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8 patients showed symptomatic heart failure due to FA

Nine patients showed symptomatic heart failure, which was due to FA in eight cases. Most showed heart enlargement and five had been initially diagnosed with viral myocarditis, an inflammation of the heart muscle due to a virus, despite lack of evidence.

Of the eight patients with FA-related heart failure, two underwent a heart transplant and one had surgery for an automatic implantable cardioverter defibrillator, which is a battery-powered device to restore regular heart rhythm. In the other five, ejection fraction (the percentage of blood pumped from the left ventricle with each heartbeat) was normalized.

Among patients with cardiac issues as first symptoms, a diagnosis of FA basely solely on these symptoms was reached in three cases. Five patients were diagnosed when neurological symptoms followed.

On average, cardiac symptom onset occurred at a mean age of 7.2 years, whereas FA diagnosis was reached later, by 9.9 years of age. In one patient, cardiac symptoms preceded neurologic symptoms by up to five years.

Overall, these findings suggest “earlier identification of [FA] might occur through enhancing awareness of [FA] among pediatric cardiologists who see such patients,” the researchers concluded.